1. Field of the Invention
This invention relates to the field of input devices and more particularly to scaled input devices which can indicate selection of an input value from a range of permissible values.
2. Art Background
As the functions and capabilities of processor/microprocessor controlled machines/systems continue to increase, the need for user friendly and specifically tailored input devices also increase. For example, the mouse was developed to complement the traditional keyboard to facilitate easier cursor control and user selection of command options from pull down menus. Likewise, the joystick was developed to facilitate easier object movement and user selection of actions at certain locations. For a discussion of other widely used input devices, see Foley, J. D. & Van Dam, A., Fundamentals of Interactive Computer Graphics, (Addison-Wesley 1984), pp. 127-129.
In many of these processor/microprocessor controlled machines/systems, it is often desirable to allow the user to interactively select an input value from a range of permissible values. For example, scaled input devices such as dimmers or faders may be used to allow the user to indicate his/her selection. In a typical dimmer or fader device, a rotating knob or a sliding bar is used to facilitate the selection of the input value from the range of permissible values. The rotating knob or the sliding bar is a potentiometer or coupled to potentiometers that provide signals to indicate the selected input value. Some rotating knobs have multi-turn capabilities for improved resolution and range.
One common disadvantage of these dimmer or fader devices found in the prior art is that the range of permissible values available for selection and the resolution of the selectable values are often fixed. Thus, neither the range nor the resolution can be changed by the user. Furthermore, the range and the resolution provided by these devices are often limited. The configuration of these devices is such that a trade off exists between the range offered and the resolution offered. If the range is increased, the resolution must be decreased to stay within the physical limits of the device. Likewise, if the resolution is increased, the range must be decreased. Thus, the limitations are often too restrictive for a user who requires a wide range as well as a high degree of resolution.
In addition, these dimmer or fader devices provide little or no feedback to the user. For example, the user may not be `informed` by the device of the current location of operation within the range of permissible values available for selection or how close to the outer limits of the range the user is operating. If any feedback is provided, external means such as a display is used in conjunction with the device.